when Jasper Lawrence learned that hookworms might lessen the effects of his allergies, he set out on a unique mission: to travel to West Africa and purposefully become infected with the parasite.
To be specific, he stamped around barefoot in latrines. The next spring? Allergies gone. Now he sells hookworms he harvests from his own feces.
Here is a NY Times article on the proposed hookworm-allergy link.
The claim: humans evolved with parasites, and some have positive side effects. Purging our systems and enviroment of the worms upsets our internal ecology. Asthma and allergies are one consequence.